1. Field of the Invention
The present invention relates to an automotive dynamoelectric machine that includes an inverter power circuit, and has a generating function and a motor mechanism, and particularly relates to a construction of a metal member that enables input and output of electric power to and from the inverter power circuit.
2. Description of the Related Art
Conventional automotive alternators include a rectifier that is constituted by: a positive-side heatsink that is shaped so as to have an approximate C shape, and on a front surface of which positive-side diodes are mounted; a negative-side heatsink that is shaped so as to have an approximate C shape, and on a front surface of which negative-side diodes are mounted; a circuit board that is shaped so as to have an approximate C shape, and into which inserted conductors for connecting the positive-side and negative-side diodes are insert molded; and an output terminal bolt that is knurled and press fitted into one circumferential end portion of the positive-side heatsink (see Patent Literature 1, for example).
The negative-side heatsink is disposed radially outside the positive-side heatsink, and the circuit board is disposed in front of the negative-side heatsink. In addition, flange portions that are disposed so as to extend radially outward from two circumferential sides and a central portion of the positive-side heatsink are interposed between the negative-side heatsink and the circuit board so as to ensure electrical insulation. The rectifier is mounted to the rear bracket by fastening mounting screws to an inner wall surface of the rear bracket that are passed through at three positions that include two circumferential sides and a central portion of a laminated body that is constituted by the positive-side heatsink, the negative-side heatsink, and the circuit board that have been stacked together.
Patent Literature 1; Japanese Patent Laid-Open No. 2008-295116 (Gazette)
In conventional automotive alternators, the negative-side heatsink is electrically connected to the rear bracket, which is kept at ground electric potential, and the positive-side heatsink is kept at battery electric potential by means of the output terminal bolt. Thus, if salt water, etc., enters a conventional automotive alternator, galvanic corrosion of the positive-side heatsink may occur. Fins on the positive-side heatsink are thereby reduced, making cooling performance of the positive-side heatsink deteriorate, and one problem has been that the temperature of the positive-side diodes may rise excessively.